PB2291: STATUS OF IRREGULAR ANTIBODIES IN THE COVID ERA: A NEW PRESSURE FOR THE TRANSFUSION DEPARTMENT?
Authors: H. Fernandez Leyva
Journal: HemaSphere (2022)

Background: Despite the introduction of robust detection programs into clinical practice, alloimmunisation remains a problem, particularly in the context of increased transfusion requirements and RhD pregnancy-induced alloimmunisation. Antibody identification was performed only on patients who tested positive in the screening test. From the total number of patients who were screened for unexpected antibodies (1.01%) tested positive. The Rh blood group system antibodies were the most frequent, particularly anti-D. Alloimmunization to red cell antigens is still a current problem in our transfusion practice. It is obvious that the additional testing of blood donors for Rh and Kell antigens should be implemented as routine to prevent as far as possible the incidence of alloimmunization. It would also be cost-effective, bearing in mind the additional laboratory testing necessary to provide compatible blood for alloimmunized patients. Aims: This research aims to assess the prevalence of unexpected antibodies and their correlation with several clinical conditions. Due to the high prevalence of acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the pressure of the transfusion department raised proportionally. Evaluation of ABO, RhD and blood group antigen frequencies in blood donors as well as the incidence of alloimmunization in transfused patients. The need for routine typing of certain blood group antigens in addition to ABO and RhD was also evaluated. Methods: In this cross-sectional prospective study we evaluated data from 542 ABO/Rh and Kell typed blood donors undertaken from January 2020 to January 2022, as well as the data from pre-transfusion testing included ABO, RhD grouping, cross-matching, irregular red blood cell antibody screening and compatibility testing identification in the mention period. All tests were performed by the DiaMed tube gel system. Results: The frequencies of ABO antigens were as follows: O (48.5%), A (29.9%), B (17.2%), AB (7.4%). The frequencies of Rh antigens were as follows: D positive. (85.3%), D negative. (13.6%), C (28.3%), c (32.4%), E (19.3%), e (37.8%). We found the following frequencies of Kell phenotypes: K+ k- (0.25%), K+ k+ (6.18%), and K- k+ (25.6%) with the total frequency of K antigen of 4.4%. Antibody screening and/or cross-match were positive in the sera from 64 transfused patients. In 42 sera the following 81 antibodies were identified: anti-K (36), -E (5), -e (1), -C (2), -c (2), -C(w) (2), -k (1), -Fy (a) (3), -Fy(b) (1), -Jk(a) (3), -Lu(b) (1), -Le(b) (2), -Le(a) (1), -M (3), -P1 (1). The most frequent alloantibody was anti-K with 32%, and anti-E with 11.3% of all identified antibodies. Summary/Conclusion: There was also a significant correlation between the unexpected antibodies and history of transfusion, pregnancy, and autoimmune diseases as P ≤ 0.05. The most prominent unexpected antibodies in the study belong to the Rh system (Anti-D). Extended blood typing is regularly implemented for some polytransfused patients. This strategy is a step forward to improve the safety of blood transfusion with optimal blood grouping. More to the point, because of the strong correlation between the unexpected antibodies as well as the history of transfusion, pregnancy, and autoimmune diseases, the highest safety criteria must be followed during the transfusion of blood to patients with these clinical conditions.